无穷级数问题1.数列通项1/n数列发散还是收敛2.数列通项1/(n的平方）数列发散还是收敛>"

Answer 1

(1)取m=2n
绝对值（xm-xn)=1/(n+1)+1/(n+2)+...+1/2n>1/2n+1/2n+...+1/2n=1/2
(2)设m>n
绝对值（xm-xn)=1/(n+1)^2+...+1/m^2